Mobile telephones are known in the practice. These also include the so-called smartphones, which are capable of performing many additional functions besides the actual telecommunication functions in the strict sense. Such smartphones comprise processor systems, in the storage means of which various application programs, so-called apps, can be stored.
Mobile telephones have internal clocks, which specify, show and constantly update the internal device time. This internal device time is not necessarily required for calls, but is used for many functions of a mobile telephone, from telephone-internal protocol routines to sending time information in connection with application programs.
In some applications it is desirable that a review of the real time of an application can be detected and reconstructed. This is especially true in cases where in an application a data stream must be sent to a recipient within a predefined time window.
The resulting problem is that by the recipient, a real time for example based on atomic clocks or timing signals synchronized therewith can be generated and maintained. In contrast, mobile telephones usually include own time standards, which may have deviations from the real time. Thus, the device time of a mobile telephone may considerably differ from the real time. Consequently, a transmission of a data stream from the mobile telephone to a recipient within a time window cannot easily be verified, if the data stream only contains information about the timing of operation of the mobile telephone based on a read-out of the device time. This can ultimately cause erroneous further processing of such data streams, which, though generated within a predetermined time window of the real time, however contain a device time, which due to clock drifts is outside of the time window.